blob: 8082d9875d6ba01c068b1ee1ae16081c4caa00fc [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/acct.c
3 *
4 * BSD Process Accounting for Linux
5 *
6 * Author: Marco van Wieringen <mvw@planets.elm.net>
7 *
8 * Some code based on ideas and code from:
9 * Thomas K. Dyas <tdyas@eden.rutgers.edu>
10 *
11 * This file implements BSD-style process accounting. Whenever any
12 * process exits, an accounting record of type "struct acct" is
13 * written to the file specified with the acct() system call. It is
14 * up to user-level programs to do useful things with the accounting
15 * log. The kernel just provides the raw accounting information.
16 *
17 * (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
18 *
19 * Plugged two leaks. 1) It didn't return acct_file into the free_filps if
20 * the file happened to be read-only. 2) If the accounting was suspended
21 * due to the lack of space it happily allowed to reopen it and completely
22 * lost the old acct_file. 3/10/98, Al Viro.
23 *
24 * Now we silently close acct_file on attempt to reopen. Cleaned sys_acct().
25 * XTerms and EMACS are manifestations of pure evil. 21/10/98, AV.
26 *
27 * Fixed a nasty interaction with with sys_umount(). If the accointing
28 * was suspeneded we failed to stop it on umount(). Messy.
29 * Another one: remount to readonly didn't stop accounting.
30 * Question: what should we do if we have CAP_SYS_ADMIN but not
31 * CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY
32 * unless we are messing with the root. In that case we are getting a
33 * real mess with do_remount_sb(). 9/11/98, AV.
34 *
35 * Fixed a bunch of races (and pair of leaks). Probably not the best way,
36 * but this one obviously doesn't introduce deadlocks. Later. BTW, found
37 * one race (and leak) in BSD implementation.
38 * OK, that's better. ANOTHER race and leak in BSD variant. There always
39 * is one more bug... 10/11/98, AV.
40 *
41 * Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold
42 * ->mmap_sem to walk the vma list of current->mm. Nasty, since it leaks
43 * a struct file opened for write. Fixed. 2/6/2000, AV.
44 */
45
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#include <linux/mm.h>
47#include <linux/slab.h>
48#include <linux/acct.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080049#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050#include <linux/file.h>
51#include <linux/tty.h>
52#include <linux/security.h>
53#include <linux/vfs.h>
54#include <linux/jiffies.h>
55#include <linux/times.h>
56#include <linux/syscalls.h>
Al Viro7b7b1ac2005-11-07 17:13:39 -050057#include <linux/mount.h>
Paul McQuade7153e402014-06-06 14:37:37 -070058#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070059#include <asm/div64.h>
60#include <linux/blkdev.h> /* sector_div */
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -070061#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63/*
64 * These constants control the amount of freespace that suspend and
65 * resume the process accounting system, and the time delay between
66 * each check.
67 * Turned into sysctl-controllable parameters. AV, 12/11/98
68 */
69
70int acct_parm[3] = {4, 2, 30};
71#define RESUME (acct_parm[0]) /* >foo% free space - resume */
72#define SUSPEND (acct_parm[1]) /* <foo% free space - suspend */
73#define ACCT_TIMEOUT (acct_parm[2]) /* foo second timeout between checks */
74
75/*
76 * External references and all of the globals.
77 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -070078static void do_acct_process(struct bsd_acct_struct *acct,
79 struct pid_namespace *ns, struct file *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
81/*
82 * This structure is used so that all the data protected by lock
83 * can be placed in the same cache line as the lock. This primes
84 * the cache line to have the data after getting the lock.
85 */
Pavel Emelyanov081e4c82008-07-25 01:48:42 -070086struct bsd_acct_struct {
Al Viro32dc7302011-12-08 20:08:42 -050087 int active;
88 unsigned long needcheck;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 struct file *file;
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -070090 struct pid_namespace *ns;
Pavel Emelyanovb5a71742008-07-25 01:48:47 -070091 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092};
93
Pavel Emelyanova75d9792008-07-25 01:48:45 -070094static DEFINE_SPINLOCK(acct_lock);
Pavel Emelyanovb5a71742008-07-25 01:48:47 -070095static LIST_HEAD(acct_list);
Pavel Emelyanova75d9792008-07-25 01:48:45 -070096
Linus Torvalds1da177e2005-04-16 15:20:36 -070097/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 * Check the amount of free space and suspend/resume accordingly.
99 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700100static int check_free_space(struct bsd_acct_struct *acct, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101{
102 struct kstatfs sbuf;
103 int res;
104 int act;
Al Viro32dc7302011-12-08 20:08:42 -0500105 u64 resume;
106 u64 suspend;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700108 spin_lock(&acct_lock);
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700109 res = acct->active;
Al Viro32dc7302011-12-08 20:08:42 -0500110 if (!file || time_is_before_jiffies(acct->needcheck))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 goto out;
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700112 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 /* May block */
Christoph Hellwigebabe9a2010-07-07 18:53:11 +0200115 if (vfs_statfs(&file->f_path, &sbuf))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 return res;
117 suspend = sbuf.f_blocks * SUSPEND;
118 resume = sbuf.f_blocks * RESUME;
119
Al Viro32dc7302011-12-08 20:08:42 -0500120 do_div(suspend, 100);
121 do_div(resume, 100);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
123 if (sbuf.f_bavail <= suspend)
124 act = -1;
125 else if (sbuf.f_bavail >= resume)
126 act = 1;
127 else
128 act = 0;
129
130 /*
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700131 * If some joker switched acct->file under us we'ld better be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 * silent and _not_ touch anything.
133 */
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700134 spin_lock(&acct_lock);
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700135 if (file != acct->file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 if (act)
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700137 res = act > 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 goto out;
139 }
140
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700141 if (acct->active) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 if (act < 0) {
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700143 acct->active = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 printk(KERN_INFO "Process accounting paused\n");
145 }
146 } else {
147 if (act > 0) {
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700148 acct->active = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 printk(KERN_INFO "Process accounting resumed\n");
150 }
151 }
152
Al Viro32dc7302011-12-08 20:08:42 -0500153 acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700154 res = acct->active;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155out:
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700156 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 return res;
158}
159
160/*
Randy Dunlap417ef532005-09-10 00:26:39 -0700161 * Close the old accounting file (if currently open) and then replace
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 * it with file (if non-NULL).
163 *
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700164 * NOTE: acct_lock MUST be held on entry and exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 */
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700166static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
167 struct pid_namespace *ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168{
169 struct file *old_acct = NULL;
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -0700170 struct pid_namespace *old_ns = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700172 if (acct->file) {
173 old_acct = acct->file;
174 old_ns = acct->ns;
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700175 acct->active = 0;
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700176 acct->file = NULL;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700177 acct->ns = NULL;
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700178 list_del(&acct->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 }
180 if (file) {
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700181 acct->file = file;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700182 acct->ns = ns;
Al Viro32dc7302011-12-08 20:08:42 -0500183 acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700184 acct->active = 1;
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700185 list_add(&acct->list, &acct_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 }
187 if (old_acct) {
Josef "Jeff" Sipekf3a43f32006-12-08 02:36:43 -0800188 mnt_unpin(old_acct->f_path.mnt);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700189 spin_unlock(&acct_lock);
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700190 do_acct_process(acct, old_ns, old_acct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 filp_close(old_acct, NULL);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700192 spin_lock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 }
194}
195
Jeff Layton669abf42012-10-10 16:43:10 -0400196static int acct_on(struct filename *pathname)
Al Viro7b7b1ac2005-11-07 17:13:39 -0500197{
198 struct file *file;
Renaud Lottiauxdf279ca2009-06-30 11:41:34 -0700199 struct vfsmount *mnt;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700200 struct pid_namespace *ns;
201 struct bsd_acct_struct *acct = NULL;
Al Viro7b7b1ac2005-11-07 17:13:39 -0500202
203 /* Difference from BSD - they don't do O_APPEND */
Jeff Layton669abf42012-10-10 16:43:10 -0400204 file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500205 if (IS_ERR(file))
206 return PTR_ERR(file);
207
Al Viro496ad9a2013-01-23 17:07:38 -0500208 if (!S_ISREG(file_inode(file)->i_mode)) {
Al Viro7b7b1ac2005-11-07 17:13:39 -0500209 filp_close(file, NULL);
210 return -EACCES;
211 }
212
213 if (!file->f_op->write) {
214 filp_close(file, NULL);
215 return -EIO;
216 }
217
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700218 ns = task_active_pid_ns(current);
219 if (ns->bacct == NULL) {
220 acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
221 if (acct == NULL) {
222 filp_close(file, NULL);
223 return -ENOMEM;
224 }
225 }
226
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700227 spin_lock(&acct_lock);
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700228 if (ns->bacct == NULL) {
229 ns->bacct = acct;
230 acct = NULL;
231 }
232
Renaud Lottiauxdf279ca2009-06-30 11:41:34 -0700233 mnt = file->f_path.mnt;
234 mnt_pin(mnt);
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700235 acct_file_reopen(ns->bacct, file, ns);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700236 spin_unlock(&acct_lock);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500237
Renaud Lottiauxdf279ca2009-06-30 11:41:34 -0700238 mntput(mnt); /* it's pinned, now give up active reference */
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700239 kfree(acct);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500240
241 return 0;
242}
243
Randy Dunlap417ef532005-09-10 00:26:39 -0700244/**
245 * sys_acct - enable/disable process accounting
246 * @name: file name for accounting records or NULL to shutdown accounting
247 *
248 * Returns 0 for success or negative errno values for failure.
249 *
250 * sys_acct() is the only system call needed to implement process
251 * accounting. It takes the name of the file where accounting records
252 * should be written. If the filename is NULL, accounting will be
253 * shutdown.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 */
Heiko Carstensb290ebe2009-01-14 14:14:06 +0100255SYSCALL_DEFINE1(acct, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256{
Eric Paris05b90492010-04-07 15:15:25 -0400257 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
259 if (!capable(CAP_SYS_PACCT))
260 return -EPERM;
261
262 if (name) {
Jeff Layton91a27b22012-10-10 15:25:28 -0400263 struct filename *tmp = getname(name);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500264 if (IS_ERR(tmp))
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700265 return PTR_ERR(tmp);
Jeff Layton669abf42012-10-10 16:43:10 -0400266 error = acct_on(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 putname(tmp);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500268 } else {
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700269 struct bsd_acct_struct *acct;
270
271 acct = task_active_pid_ns(current)->bacct;
272 if (acct == NULL)
273 return 0;
274
Eric Paris05b90492010-04-07 15:15:25 -0400275 spin_lock(&acct_lock);
276 acct_file_reopen(acct, NULL, NULL);
277 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 }
Eric Paris05b90492010-04-07 15:15:25 -0400279
Al Viro7b7b1ac2005-11-07 17:13:39 -0500280 return error;
281}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
Al Viro7b7b1ac2005-11-07 17:13:39 -0500283/**
284 * acct_auto_close - turn off a filesystem's accounting if it is on
285 * @m: vfsmount being shut down
286 *
287 * If the accounting is turned on for a file in the subtree pointed to
288 * to by m, turn accounting off. Done when m is about to die.
289 */
290void acct_auto_close_mnt(struct vfsmount *m)
291{
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700292 struct bsd_acct_struct *acct;
293
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700294 spin_lock(&acct_lock);
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700295restart:
296 list_for_each_entry(acct, &acct_list, list)
297 if (acct->file && acct->file->f_path.mnt == m) {
298 acct_file_reopen(acct, NULL, NULL);
299 goto restart;
300 }
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700301 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302}
303
Randy Dunlap417ef532005-09-10 00:26:39 -0700304/**
305 * acct_auto_close - turn off a filesystem's accounting if it is on
306 * @sb: super block for the filesystem
307 *
308 * If the accounting is turned on for a file in the filesystem pointed
309 * to by sb, turn accounting off.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 */
311void acct_auto_close(struct super_block *sb)
312{
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700313 struct bsd_acct_struct *acct;
314
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700315 spin_lock(&acct_lock);
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700316restart:
317 list_for_each_entry(acct, &acct_list, list)
Al Virod8c95842011-12-07 18:16:57 -0500318 if (acct->file && acct->file->f_path.dentry->d_sb == sb) {
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700319 acct_file_reopen(acct, NULL, NULL);
320 goto restart;
321 }
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700322 spin_unlock(&acct_lock);
323}
324
325void acct_exit_ns(struct pid_namespace *ns)
326{
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700327 struct bsd_acct_struct *acct = ns->bacct;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700328
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700329 if (acct == NULL)
330 return;
331
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700332 spin_lock(&acct_lock);
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700333 if (acct->file != NULL)
334 acct_file_reopen(acct, NULL, NULL);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700335 spin_unlock(&acct_lock);
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700336
337 kfree(acct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338}
339
340/*
341 * encode an unsigned long into a comp_t
342 *
343 * This routine has been adopted from the encode_comp_t() function in
344 * the kern_acct.c file of the FreeBSD operating system. The encoding
345 * is a 13-bit fraction with a 3-bit (base 8) exponent.
346 */
347
348#define MANTSIZE 13 /* 13 bit mantissa. */
349#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
350#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
351
352static comp_t encode_comp_t(unsigned long value)
353{
354 int exp, rnd;
355
356 exp = rnd = 0;
357 while (value > MAXFRACT) {
358 rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */
359 value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
360 exp++;
361 }
362
363 /*
Daniel Walker6ae965c2007-10-18 03:06:04 -0700364 * If we need to round up, do it (and handle overflow correctly).
365 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 if (rnd && (++value > MAXFRACT)) {
367 value >>= EXPSIZE;
368 exp++;
369 }
370
371 /*
Daniel Walker6ae965c2007-10-18 03:06:04 -0700372 * Clean it up and polish it off.
373 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 exp <<= MANTSIZE; /* Shift the exponent into place */
375 exp += value; /* and add on the mantissa. */
376 return exp;
377}
378
379#if ACCT_VERSION==1 || ACCT_VERSION==2
380/*
381 * encode an u64 into a comp2_t (24 bits)
382 *
383 * Format: 5 bit base 2 exponent, 20 bits mantissa.
384 * The leading bit of the mantissa is not stored, but implied for
385 * non-zero exponents.
386 * Largest encodable value is 50 bits.
387 */
388
389#define MANTSIZE2 20 /* 20 bit mantissa. */
390#define EXPSIZE2 5 /* 5 bit base 2 exponent. */
391#define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */
392#define MAXEXP2 ((1 <<EXPSIZE2) - 1) /* Maximum exponent. */
393
394static comp2_t encode_comp2_t(u64 value)
395{
Daniel Walker6ae965c2007-10-18 03:06:04 -0700396 int exp, rnd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
Daniel Walker6ae965c2007-10-18 03:06:04 -0700398 exp = (value > (MAXFRACT2>>1));
399 rnd = 0;
400 while (value > MAXFRACT2) {
401 rnd = value & 1;
402 value >>= 1;
403 exp++;
404 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405
Daniel Walker6ae965c2007-10-18 03:06:04 -0700406 /*
407 * If we need to round up, do it (and handle overflow correctly).
408 */
409 if (rnd && (++value > MAXFRACT2)) {
410 value >>= 1;
411 exp++;
412 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413
Daniel Walker6ae965c2007-10-18 03:06:04 -0700414 if (exp > MAXEXP2) {
415 /* Overflow. Return largest representable number instead. */
416 return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1;
417 } else {
418 return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1));
419 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420}
421#endif
422
423#if ACCT_VERSION==3
424/*
425 * encode an u64 into a 32 bit IEEE float
426 */
427static u32 encode_float(u64 value)
428{
429 unsigned exp = 190;
430 unsigned u;
431
432 if (value==0) return 0;
433 while ((s64)value > 0){
434 value <<= 1;
435 exp--;
436 }
437 u = (u32)(value >> 40) & 0x7fffffu;
438 return u | (exp << 23);
439}
440#endif
441
442/*
443 * Write an accounting entry for an exiting process
444 *
445 * The acct_process() call is the workhorse of the process
446 * accounting system. The struct acct is built here and then written
447 * into the accounting file. This function should only be called from
Ingo Molnarbcbe4a02007-11-26 21:21:49 +0100448 * do_exit() or when switching to a different output file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 */
450
451/*
452 * do_acct_process does all actual work. Caller holds the reference to file.
453 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700454static void do_acct_process(struct bsd_acct_struct *acct,
455 struct pid_namespace *ns, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456{
KaiGai Kohei0e464812006-06-25 05:49:24 -0700457 struct pacct_struct *pacct = &current->signal->pacct;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 acct_t ac;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 unsigned long flim;
Thomas Gleixnerccbf62d2014-07-16 21:04:34 +0000460 u64 elapsed, run_time;
Peter Zijlstra24ec8392006-12-08 02:36:04 -0800461 struct tty_struct *tty;
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700462 const struct cred *orig_cred;
463
Al Viroed447242014-04-19 14:37:20 -0400464 /*
465 * Accounting records are not subject to resource limits.
466 */
467 flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
468 current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700469 /* Perform file operations on behalf of whoever enabled accounting */
470 orig_cred = override_creds(file->f_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471
472 /*
473 * First check to see if there is enough free_space to continue
474 * the process accounting system.
475 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700476 if (!check_free_space(acct, file))
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700477 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478
479 /*
480 * Fill the accounting struct with the needed info as recorded
481 * by the different kernel functions.
482 */
Al Viro32dc7302011-12-08 20:08:42 -0500483 memset(&ac, 0, sizeof(acct_t));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484
485 ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER;
486 strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm));
487
488 /* calculate run_time in nsec*/
Thomas Gleixnerccbf62d2014-07-16 21:04:34 +0000489 run_time = ktime_get_ns();
490 run_time -= current->group_leader->start_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 /* convert nsec -> AHZ */
492 elapsed = nsec_to_AHZ(run_time);
493#if ACCT_VERSION==3
494 ac.ac_etime = encode_float(elapsed);
495#else
496 ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
497 (unsigned long) elapsed : (unsigned long) -1l);
498#endif
499#if ACCT_VERSION==1 || ACCT_VERSION==2
500 {
501 /* new enlarged etime field */
502 comp2_t etime = encode_comp2_t(elapsed);
503 ac.ac_etime_hi = etime >> 16;
504 ac.ac_etime_lo = (u16) etime;
505 }
506#endif
507 do_div(elapsed, AHZ);
john stultz2c6b47d2007-07-24 17:47:43 -0700508 ac.ac_btime = get_seconds() - elapsed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 /* we really need to bite the bullet and change layout */
Eric W. Biedermanf8f3d4d2012-02-07 16:54:50 -0800510 ac.ac_uid = from_kuid_munged(file->f_cred->user_ns, orig_cred->uid);
511 ac.ac_gid = from_kgid_munged(file->f_cred->user_ns, orig_cred->gid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512#if ACCT_VERSION==2
513 ac.ac_ahz = AHZ;
514#endif
515#if ACCT_VERSION==1 || ACCT_VERSION==2
516 /* backward-compatible 16 bit fields */
David Howells76aac0e2008-11-14 10:39:12 +1100517 ac.ac_uid16 = ac.ac_uid;
518 ac.ac_gid16 = ac.ac_gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519#endif
520#if ACCT_VERSION==3
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -0700521 ac.ac_pid = task_tgid_nr_ns(current, ns);
Pavel Emelyanova846a192008-03-24 12:29:52 -0700522 rcu_read_lock();
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -0700523 ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent), ns);
Pavel Emelyanova846a192008-03-24 12:29:52 -0700524 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525#endif
526
OGAWA Hirofumia4afee02006-07-14 00:24:18 -0700527 spin_lock_irq(&current->sighand->siglock);
Alan Coxdbda4c02008-10-13 10:40:53 +0100528 tty = current->signal->tty; /* Safe as we hold the siglock */
Oleg Nesterov7bcfa952006-12-08 02:36:07 -0800529 ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700530 ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
531 ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700532 ac.ac_flag = pacct->ac_flag;
KaiGai Kohei0e464812006-06-25 05:49:24 -0700533 ac.ac_mem = encode_comp_t(pacct->ac_mem);
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700534 ac.ac_minflt = encode_comp_t(pacct->ac_minflt);
535 ac.ac_majflt = encode_comp_t(pacct->ac_majflt);
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700536 ac.ac_exitcode = pacct->ac_exitcode;
OGAWA Hirofumia4afee02006-07-14 00:24:18 -0700537 spin_unlock_irq(&current->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538
539 /*
Jan Kara5ae98f12013-05-04 00:11:23 +0200540 * Get freeze protection. If the fs is frozen, just skip the write
541 * as we could deadlock the system otherwise.
542 */
Al Viroed447242014-04-19 14:37:20 -0400543 if (file_start_write_trylock(file)) {
544 /* it's been opened O_APPEND, so position is irrelevant */
545 loff_t pos = 0;
546 __kernel_write(file, (char *)&ac, sizeof(acct_t), &pos);
547 file_end_write(file);
548 }
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700549out:
Al Viroed447242014-04-19 14:37:20 -0400550 current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700551 revert_creds(orig_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552}
553
Randy Dunlap417ef532005-09-10 00:26:39 -0700554/**
KaiGai Kohei0e464812006-06-25 05:49:24 -0700555 * acct_collect - collect accounting information into pacct_struct
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700556 * @exitcode: task exit code
557 * @group_dead: not 0, if this thread is the last one in the process.
KaiGai Kohei0e464812006-06-25 05:49:24 -0700558 */
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700559void acct_collect(long exitcode, int group_dead)
KaiGai Kohei0e464812006-06-25 05:49:24 -0700560{
561 struct pacct_struct *pacct = &current->signal->pacct;
Frederic Weisbecker6fac4822012-11-13 14:20:55 +0100562 cputime_t utime, stime;
KaiGai Kohei0e464812006-06-25 05:49:24 -0700563 unsigned long vsize = 0;
564
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700565 if (group_dead && current->mm) {
KaiGai Kohei0e464812006-06-25 05:49:24 -0700566 struct vm_area_struct *vma;
567 down_read(&current->mm->mmap_sem);
568 vma = current->mm->mmap;
569 while (vma) {
570 vsize += vma->vm_end - vma->vm_start;
571 vma = vma->vm_next;
572 }
573 up_read(&current->mm->mmap_sem);
574 }
575
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700576 spin_lock_irq(&current->sighand->siglock);
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700577 if (group_dead)
578 pacct->ac_mem = vsize / 1024;
579 if (thread_group_leader(current)) {
580 pacct->ac_exitcode = exitcode;
581 if (current->flags & PF_FORKNOEXEC)
582 pacct->ac_flag |= AFORK;
583 }
584 if (current->flags & PF_SUPERPRIV)
585 pacct->ac_flag |= ASU;
586 if (current->flags & PF_DUMPCORE)
587 pacct->ac_flag |= ACORE;
588 if (current->flags & PF_SIGNALED)
589 pacct->ac_flag |= AXSIG;
Frederic Weisbecker6fac4822012-11-13 14:20:55 +0100590 task_cputime(current, &utime, &stime);
591 pacct->ac_utime += utime;
592 pacct->ac_stime += stime;
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700593 pacct->ac_minflt += current->min_flt;
594 pacct->ac_majflt += current->maj_flt;
595 spin_unlock_irq(&current->sighand->siglock);
KaiGai Kohei0e464812006-06-25 05:49:24 -0700596}
597
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700598static void acct_process_in_ns(struct pid_namespace *ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599{
600 struct file *file = NULL;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700601 struct bsd_acct_struct *acct;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700603 acct = ns->bacct;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 /*
605 * accelerate the common fastpath:
606 */
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700607 if (!acct || !acct->file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 return;
609
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700610 spin_lock(&acct_lock);
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700611 file = acct->file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 if (unlikely(!file)) {
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700613 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 return;
615 }
616 get_file(file);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700617 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700619 do_acct_process(acct, ns, file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 fput(file);
621}
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700622
623/**
Pavel Emelyanov0c18d7a2008-07-25 01:48:49 -0700624 * acct_process - now just a wrapper around acct_process_in_ns,
625 * which in turn is a wrapper around do_acct_process.
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700626 *
627 * handles process accounting for an exiting task
628 */
629void acct_process(void)
630{
631 struct pid_namespace *ns;
632
Pavel Emelyanov0c18d7a2008-07-25 01:48:49 -0700633 /*
634 * This loop is safe lockless, since current is still
635 * alive and holds its namespace, which in turn holds
636 * its parent.
637 */
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700638 for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
639 acct_process_in_ns(ns);
640}